1. Field of the Invention
The present invention relates to a system and a method for inspecting a light source included in an image reader comprising a photoelectric converter.
2. Description of the Related Art
Image readers of a reflection-original scanner, a photo-film scanner and so forth are known. In such image readers, an image recorded on an original is photoelectrically read. The image reader comprises a light source and a phtooelectric converter. The light source emits the light to the original. The photoelectric converter receives the light and converts it into an electric signal to be outputted.
As to the photoelectric converter, a charge coupled device (CCD) is used, for example. As to the light source, an LED unit is used, for example. The LED unit includes a large number of light emitting elements, which are arranged to emit the light of respective colors of blue (B), green (G) and red (R). Further, the LED unit includes another light emitting element for radiating infrared rays (IR) used for detecting dust, a scratch and so forth on a photographic film. The infrared rays are also used for detecting positions of the dust, the scratch and so forth. On the basis of data obtained by using the infrared rays, image correction is executed.
In case some of the light emitting elements fail or a driver for controlling them fails, some of the light emitting elements are not turned on and a light amount thereof decreases. If such failure of the light source occurs on the light emitting elements of B, G and R, the light amount lacks on a print surface and unevenness of the light amount is likely to be caused thereon. Meanwhile, if such failure occurs on the light emitting element of the infrared rays, it becomes impossible to correct the dust, the scratch and so forth of the photographic film. In view of this, the light source is periodically inspected or is inspected as occasion demands, in order to confirm lighting states of the respective light emitting elements.
For example, the light source is inspected by watching the LED unit in a state that the light emitting elements are turned on every color. With respect to the light emitting elements of R, G and B, the lighting state thereof is confirmed by directly viewing each color of the light. With respect to the light emitting element of the infrared rays, the lighting state thereof is confirmed by viewing the infrared rays through an IR scope, because it is invisible.
However, there is a problem in that it is difficult to find the broken light emitting element, since a large number of the light emitting elements are arranged in extremely short intervals. Moreover, there is another problem in that an inspecting operation is troublesome, since the IR scope and so forth are necessary to inspect the light emitting elements of the infrared rays. In addition, when light intensity of the light emitting element is high, there is a possibility that a human eye is affected by directly watching it.